1. Field of the Invention
The present invention relates, generally, to crop harvesting systems, apparatus and methods. Particularly, the invention relates to hay harvesting systems, apparatus and methods. The present invention is most particularly suitable for use in and for large rectangular (often called “square”) hay balers.
2. Background Information
Harvesting baled hay at the correct moisture is difficult due to the variation in moisture of the crop as it is close to the target moisture for baling of 13% to 16%. Hay harvested below that level is too dry leading to excess losses due to shatter and hay harvested above that level is too wet leading to spoilage of the crop in storage. Due to the variation, moisture monitoring devices mounted in hay baling implements have become popular with the producers of hay, giving them continuous information on the moisture of the crop as the hay is being baled.
Implement-mounted moisture monitors include electrical current based devices and radio wave based devices. Use of these monitors has become common-place in hay baling. Moisture in a bale is the most important factor in the transmission of electrical signals through the bale. Current based moisture sensors estimate hay moisture by sensing electrical transmission of current through a bale. In such devices, one positive polarity sensor is located opposite a negative polarity sensor and the continuity between the sensors is measured and associated with the moisture in the hay bale. In radio wave transmission devices, one sensor emits a radio wave signal through the bale while a second sensor receives the radio wave signal and the higher the moisture of the bale, the stronger the transmission of the radio wave signal received by the second sensor. If all other variables affecting the transmission of current or radio signals are unchanged, a change in signal transmission will result in good estimate in the level of moisture in the hay bale.
A second significant factor affecting the transmission of signals through the bale being tested during baling is the density of the bale at the point at which signal transmission is measured. The higher the density, the more transmission of the signal will occur. The density of the bale within areas of the bale can vary from 1 pound per cubic foot (loose hay) to 30 pounds per cubic foot (tightly compacted hay). To effectively monitor changes in moisture, sensors need to be located in a position where the density of the bale is somewhat consistent. A common location on the baler where density of the bale is consistent is in the baler's “chamber” (or “bale chamber”) where hay density is controlled by a combination of a plunger compressing the hay against restrictors to the flow of hay. Locating the sensors in the chamber has drawbacks however. One drawback is the delay that is required for the crop being baled to move through the baler to the chamber, which is located at the rear of the baler. Another drawback is the limitation of sensing all the crop being baled as the sensors are placed in one area of the bale and moisture in other areas can remain unseen. In cases where the hay moisture makes a rapid change over a relatively small area of the field being harvested, the bales could have significantly different moisture in different areas of the bale. If the operator of the baler is relying on the moisture being monitored by the device to determine if the hay is too dry or too wet to continue baling, the lag in readings will lead to a significant amount of hay being harvested outside the desired range before balling is suspended. In the case of preservative application systems that are controlled by input from moisture-sensing devices to regulate the amount of preservative based on the moisture of the hay it is applied to, the preservative application which has to be done to loose hay on the front of the baler to assure adequate coverage, application does not match up to the moisture in the location of application. The sensing of moisture in closer proximity to the point of application would have the advantage of closely matching preservative application to moisture content. However, density of the hay being baled has variability in areas of the baler which are located toward the front of the baler, anterior to or forward of the bale chamber, closer to the field.
The transmission of the electrical signal between sensors is also typically influenced by electrical transmission through adjacent metal parts. Such parts typically have much higher properties of transmission than hay. When the sensors are located within a baler's chamber, if all parts of the bale are not isolated from contact with metal, conductivity between the sensors can follow the pathway from the sending sensor to the closest metal surface, through the metal surface closest to the receiving sensor. In this manner, only the moisture of the hay between metal surfaces and the sensors will change the conductivity between the sensors eliminating any influence in electrical transmission from the moisture in other parts of the bale. With all types of sensors commonly in use, the close proximity of the sensors to metal results in a small amount of hay being tested for moisture. And, inside the chamber, there is a significant amount of metal surface that would have to be lined with a non-conductive material to eliminate contact between the bale and metal.
One type of rectangular baler currently in use is commonly called a “large square baler.” These are typically between twenty-four and fifty inches (24-50 in.) wide, twenty-four and fifty inches high (24-60 in.) and sixty inches and one-hundred inches (60-100 in.) long. Recent developments in the design of large square balers have added a “pre-compression chamber” to the implement that leads to the formation of a more uniform bale. In the feeding of the hay, material is held by a door or other types of flow restrictors in a pre-compression chamber just after it is picked up from the field. When the density of the hay in this chamber reaches a certain point, the door opens allowing the hay to move into the baler's chamber, forming a more consistent bale than if it moved into the chamber without pre-compression. The tension on the door is controlled by a mechanical device such as a spring and when a set tension is reached the door trips allowing the hay to move into the chamber.
In the present invention, the consistent state of hay density occurring momentarily in the pre-compression chamber just before the door opens is utilized to attain a more timely reading of moisture. Sensing moisture in this area also allows for the hay being tested to be isolated from metal parts on the baler due to the containment of the hay in this small area making it practical to line the area of the pre-compression chamber with non-conductive material.
Existing technology in this field is believed to have significant limitations and shortcomings.
All US patents and patent applications, and all other published documents mentioned anywhere in this application are incorporated by reference in their entirety.